28021785 has 24 divisors (see below), whose sum is σ = 49284480. Its totient is φ = 13585440.

The previous prime is 28021781. The next prime is 28021813. The reversal of 28021785 is 58712082.

It is not a de Polignac number, because 28021785 - 2² = 28021781 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (28021781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5905 + ... + 9534.

It is an arithmetic number, because the mean of its divisors is an integer number (2053520).

Almost surely, 2^28021785 is an apocalyptic number.

It is an amenable number.

28021785 is a deficient number, since it is larger than the sum of its proper divisors (21262695).

28021785 is a wasteful number, since it uses less digits than its factorization.

28021785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15469 (or 15458 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 28021785 is about 5293.5607109015. The cubic root of 28021785 is about 303.7376292613.

The spelling of 28021785 in words is "twenty-eight million, twenty-one thousand, seven hundred eighty-five".